<?php
/**
 * Created by PhpStorm.
 * User: wangye
 * Date: 19-3-5
 * Time: 上午9:43
 */

// 1,1,2,3,5,8,12... 30

$arr = [1,1];

for ($i=2;$i<30;$i++) {
    $arr[$i] = $arr[$i-1] + $arr[$i-2];
}
print_r($arr);
